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Preprints

Filtering by Subject: Geophysics and Seismology

Early and persistent supershear rupture of the 2018 Mw 7.5 Palu earthquake

HAN BAO, Jean Paul Ampuero, Lingsen Meng, et al.

Published: 2018-11-09
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics

Supershear earthquakes with rupture velocity exceeding shear-wave speeds, previously observed in laboratory experiments and large strike-slip events, often have an initial sub-shear stage before they transition to supershear. In this study, integrated geophysical observations of the 2018 Mw 7.5 Palu, Indonesia earthquake, provide robust evidence of an early and persistent supershear rupture [...]

A Simple Model for Deglacial Meltwater Pulses

Alexander Robel, Victor C. Tsai

Published: 2018-11-08
Subjects: Earth Sciences, Geophysics and Seismology, Glaciology, Physical Sciences and Mathematics

Evidence from radiocarbon dating and complex ice sheet modeling suggests that the fastest rate of sea level rise in Earths recent history coincided with collapse of the ice saddle between the Laurentide and Cordilleran ice sheets during the last deglaciation. In this study, we derive a simple, two-equation model of two ice sheets intersecting in an ice saddle. We show that two conditions are [...]

Co-location of the downdip end of seismic coupling and the continental shelf break

Luca Claude Malatesta, Lucile Bruhat, Noah J. Finnegan, et al.

Published: 2018-11-08
Subjects: Earth Sciences, Geomorphology, Geophysics and Seismology, Physical Sciences and Mathematics

Along subduction margins, the morphology of the near shore domain records the combined action of erosion from ocean waves and permanent tectonic deformation from the convergence of plates. We observe that at subduction margins around the globe, the edge of continental shelves tends to be located above the downdip end of seismic coupling on the megathrust (locking depth). Coastlines lie farther [...]

An investigation of multi-fault rupture scenarios using a variety of Coulomb stress modelling criteria: methods paper and full results

Mark Quigley, Abigail Jiménez, Brendan Duffy, et al.

Published: 2018-11-07
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics

A series of Coulomb stress models are used to simulate the independently-derived (Holden et al., 2011) rupture process of Mw 7.1 Darfield earthquake. The 7-fault source model of Beavan et al. (2012) is used for all models. Model differences include (i) differences in the static stress thresholds (0,1,5,10 MPa) that must be reached or exceeded to initiate rupture on a receiver fault, (ii) [...]

Growth folds above propagating normal faults

Alexander James Coleman, Oliver B. Duffy, Christopher Aiden-Lee Jackson

Published: 2018-11-07
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Stratigraphy, Tectonics and Structure

Growth folds above the upper tips of normal faults are ubiquitous in extensional settings, especially during the early phases of extension and in salt-rich basins. As slip accumulates on the underlying normal fault, the geometry and size of the fold changes. These changes reflect the dip, throw, displacement and propagation rate of the underlying normal fault, as well as the thickness and [...]

Grain friction controls characteristics of seismic cycle in rough faults with granular gouge

Omid Dorostkar, Jan Carmeliet

Published: 2018-11-02
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics

Mature faults with rough surface at their core contain granular gouge, however, the presence of fault gouge is mostly disregarded in the analysis of effect of fault’s surface roughness on the mechanics and stability of faults. In this work, we consider a rough fault system with constant roughness at the wall-gouge interaction and study the effect of grain friction on the characteristics of [...]

Overpressure Transfer Through Interconnected Igneous Intrusions

Nick Schofield, Simon Paul Holford, Alex Edwards, et al.

Published: 2018-10-30
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology

Paper looking at the transference of overpressure through interconnected igneous intrusions within sedimentary basins. The manuscript highlights the current under-recognized hazard in both scientific and hydrocarbon drilling in vicinity of subsurface igneous complexes.

Intermediate-magnitude postseismic slip follows intermediate-magnitude (M 4 to 5) earthquakes in California

Mohamed A. Alwahedi, Jessica Cleary Hawthorne

Published: 2018-10-29
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics

The magnitude of postseismic slip is useful for constraining physical models of fault slip. Here we examine the postseismic slip following intermediate-magnitude (M 4 to 5) earthquakes by systematically analyzing data from borehole strainmeters in central and northern California. We assess the noise in the data and identify 36 records from 12 earthquakes that can be interpreted. We estimate [...]

Initiation and Arrest of Earthquake Ruptures due to Elongated Overstressed Regions

Martin Galis, Jean Paul Ampuero, Paul Martin Mai, et al.

Published: 2018-10-23
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics

The initiation of natural and induced earthquakes is promoted in fault areas where the shear stress is close to fault strength. In many important situations, these overstressed fault areas (or “asperities”) are very elongated; for example, in the case of a fault intersecting a reservoir subject to fluid-injection, or the stress concentration along the bottom of a seismogenic zone induced by deep [...]

An Evaluation between Time-term, Reciprocal Time and Refraction Tomography Analysis Methods for obtaining 2-D shallow Seismic Velocity Models over Synthetic Traveltimes

Ahmed Jaddoa Al-Heety

Published: 2018-10-22
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics

Shallow seismic refraction is the principal geophysical method for environmental and engineering site investigations to image the shallow subsurface. We present an assessment of three inversion methods, namely Time-Term inversion, Reciprocal Time methods and Refraction tomography inversion by using commercial software (SeisImager™) by using a synthetic first-arrival-time dataset that was made by [...]

Disruption of Long-Term Effusive-Explosive Activity at Santiaguito, Guatemala

Oliver Lamb, Anthony Lamur, Alejandro Díax-Moreno, et al.

Published: 2018-10-19
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics, Volcanology

Rapid transitions in eruptive activity during lava dome eruptions pose significant challenges for monitoring and hazard assessment efforts. A comprehensive understanding of the dynamic evolution of active lava dome systems requires extensive multi-parametric datasets to fully constrain and understand rapid shifts in eruptive behavior, but few such datasets have been compiled. The Santiaguito lava [...]

Wavelet-based analysis of ground deformation coupling satellite acquisitions (Sentinel-1, SMOS) and data from shallow and deep wells in Southwestern France

André Burnol, Hideo Aochi, Daniel Raucoules, et al.

Published: 2018-10-15
Subjects: Aerospace Engineering, Applied Mathematics, Earth Sciences, Engineering, Geophysics and Seismology, Hydrology, Physical Sciences and Mathematics

Acquisitions of the Sentinel-1 satellite are processed and comprehensively analyzed to investigate the ground displacement during a 3-year period above a gas storage site in Southwestern France. Despite quite low vertical displacements (between 4 and 8 mm) compared to the noise level, the local displacements reflects the variations due to charge and discharge during summer and winter periods, [...]

Seismic observation of tsunami at island broadband stations

Kiwamu Nishida, Takuto Maeda, Yoshio Fukao

Published: 2018-10-15
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics

Previous studies have reported seismic observations of tsunami recorded at island broadband stations. Coastal loading by the tsunami can explain them. For further quantification, we model tsunami propagation assuming an axisymmetric structure: a conical island with a flat ocean floor. The total tsunami wavefield can be represented by superposition between an incident tsunami wave and the [...]

High-temperature shear zone formation in Carrara marble: The effect of loading conditions

Livia Nardini, Erik Rybacki, Maximilian Jacob Enzo Amandus Döhmann, et al.

Published: 2018-09-26
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure

Rock deformation at depths in the Earth’s crust is often localized in high temperature shear zones occurring at different scales in a variety of lithologies. The presence of material heterogeneities is known to trigger shear zone development, but the mechanisms controlling initiation and evolution of localization are not fully understood. To investigate the effect of loading conditions on shear [...]

Complex and cascading triggering of submarine landslides and turbidity currents at volcanic islands revealed from integration of high-resolution onshore and offshore surveys

Michael Andrew Clare, Timothy Le Bas, David Price, et al.

Published: 2018-09-22
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Hydrology, Physical Sciences and Mathematics, Sedimentology, Stratigraphy, Volcanology

Submerged flanks of volcanic islands are prone to hazards including submarine landslides that may trigger damaging tsunamis and fast-moving sediment-laden seafloor flows (turbidity currents) that break critical seafloor infrastructure. Small Island Developing States are particularly vulnerable to these hazards due to their remote and isolated nature, small size, high population densities and weak [...]

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